(1) Field of Invention
The present invention relates to a micro-electro-mechanical system (MEMS) switch, and more particularly to a balanced MEMS switch having a bias armature and an RF armature, each having their own anchors and being positioned substantially perpendicular to each other.
(2) Description of Related Art
Micro-electro-mechanical system (MEMS) switches have long been known in the art. MEMS have been formed in a myriad of designs, including an armature design. The armature design often includes an armature affixed to two anchors at both ends of the armature, with the ends separated by 180 degrees. Such an armature design tends to have an improved contact mechanism and a flatter beam. However, the stress relief mechanism of such an armature may be inferior due to its rigidness. As a result, it may be more sensitive to an environmental temperature change and has a higher actuation voltage than other designs, unless some a design technique such as a meander is adopted. The meander technique is described in an article entitled, “MEM Relay for Reconfigurable RF Circuits,” R. E. Mihailovich, Member, IEEE, M. Kim, Member, IEEE, J. B. Hacker, Member, IEEE, E. A. Sovero, Member, IEEE, J. Studer, J. A. Higgins, Fellow, IEEE, and J. F. DeNatale, in IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, Vol. 11, No. 2, February 2001. The article is incorporated herein by reference as though fully set forth herein.
U.S. Pat. No. 6,046,659, issued to Loo et al. (herein after referred to as the patent '659), discloses a MEMS switch utilizing another armature design. In the patent '659, only one end of an armature is affixed to an anchor electrode and the other end of the armature rests above a contact electrode. Due to one single anchor design and its resulting lower rigidity, it can alleviate the problems caused by the stress. However, it has two contact areas which will result in a higher contact resistance than a switch having only one contact area. In addition, the two contact areas may not reach the optimal contact condition simultaneously which can cause further contact problems.
Thus, a continuing need exists for an improved MEMS switch having a configuration that provides an improved stress relief mechanism, reduced contact resistance, a uniform actuation voltage, and that is less sensitive to a change of environmental temperature.